1. Field of the Invention
The present invention relates to paper and, more specifically, to a superamphiphobic paper.
2. Description of the Related Art
Common cellulosic paper is made from wood fibers that have been dried from a suspension in water and then pressed into a flat sheet. Typical paper (e.g., newsprint, writing paper and the like) is both hydrophilic (readily absorbs water) and oleophilic (readily absorbs oils).
In certain applications it is desirable to make paper either hydrophobic (not absorbing water), oleophobic (not absorbing oil), or both. Typically, paper is coated with layers of waxes or polymers to make it have these properties. However, such coatings can degrade over time when in contact with certain substances. Also, such coatings can introduce certain undesirable properties to the papers.
In diagnostic applications, such as biochemical assay applications, a superamphiphobic sheet (in which a drop of liquid has an apparent contact angle of greater than 150° on the sheet) can be useful. For example, a superamphiphobic sheet with a region of functionalized molecules printed thereon could be used to detect the presence of certain antibodies in blood samples or components in other bodily fluid samples to indicate the presence of a disease. The functionalized molecules would attach to the antibodies as the blood sample rolled off of the paper and a resulting change in appearance would indicate the presence of the target antibody.
In certain special applications, super-hydrophobic surfaces and super-oleophobic surfaces can be made by adding an array of nail head-shaped nanostructures onto a substrate through complex lithographic processes. However, such structures require special materials and making such structures can be cost prohibitive. Such sheets and structures are also quite rigid and fragile.
Paper, on the other hand, is made from inexpensive wood pulp. Therefore, many papers can be made quite inexpensively. Paper is also quite flexible and strong.
Therefore, there is a need for a superamphiphobic paper and a method of making superamphiphobic paper.